UI enchancements and project structure redesign

New features

• Project file structure redesign
• Introduce the YAML syntax. Dynamic YAML is possible through the INJA framework
• Support for variable number of ports
• Replace all std::string occurrancies to QString
• UI enchantments:
  • Deletion of flowgraph items. Affected connections are automatically
  • Splitter allows the user to resize the toobox tree view and the flowgraph canvas
  • Nice connection lines between blocks
  • Hovering effect on connections

Fixes

Fixes #3 (closed) #5 (closed) #7 (closed) #10 (closed) #12 (closed) #13 (closed) #15 (closed) #17 (closed)